bug#51942: cuirass postgresql deadlock

[Mathieu Othacehe]

Hello,

I observed the following deadlock on the cuirass-remote-server log file
on berlin:

--8<---------------cut here---------------start------------->8---
2021-11-17T23:12:00 fetching 
'/gnu/store/g6iqlblaxyvlvycrri110kfli9vhm8s0-julia-mlstyle-0.4.10.drv' from 
http://141.80.167.159:5558
2021-12-17T23:12:03 build succeeded: 
'/gnu/store/g6iqlblaxyvlvycrri110kfli9vhm8s0-julia-mlstyle-0.4.10In 
ice-9/eval.scm:
    619:8  2 (_ #(#(#<directory (cuirass scripts remote-server) ?> ?)))
   298:42  1 (_ #(#(#<directory (cuirass scripts remote-server) ?> ?)))
In ice-9/boot-9.scm:
  1685:16  0 (raise-exception _ #:continuable? _)
ice-9/boot-9.scm:1685:16: In procedure raise-exception:
Throw to key `psql-query-error' with args `(fatal-error "PGRES_FATAL_ERROR" 
"ERROR:  deadlock detected\nDETAIL:  Process 485 waits for ShareLock on 
transaction 760005012; blocked by process 17350.\nProcess 17350 waits for 
ShareLock on transaction 760004811; blocked by process 485.\nHINT:  See server 
log for query details.\nCONTEXT:  while rechecking updated tuple (31499,8) in 
relation \"builds\"\n")'.
2021-11-17T23:13:52 Poll loop busy during 109 seconds.
--8<---------------cut here---------------end--------------->8---

I'm not sure what can cause this issue.

Thanks,

Mathieu